Trying to decide whether to have intercalation in one of the calendrical systems in my world.

The calendar in question is based on cycles somewhat akin to the Mayan calendar.

A year is 388.866415 days long, and a synodic month is 42.235986 days long.

My current version of the calendar is made up of 37 weeks that alternate between 11 and 10 days, making a 389-day year.

Left alone, it would go ahead of the solar year by a day every ~7 years, or by a full year in 2911 years.

I'm trying to decide if it would be worth it to have a way of ommiting a day every 7 years (bearing in mind it'll be engraved into stone), or, due to the way the culture views time as a bunch of repeating cycles, if it would just make sense to not worry about trying to keep it in line with the solar year.